Linear Space - Time Coding at Full Rate and Full Diversity

| The use of multiple transmitter and receiver antennas allows to transmit multiple signal substreams in parallel and hence to increase communication capacity. In order to distribute the multiple signal substreams over the MIMO channel, linear spacetime codes have been shown to be a convenient way to reach high capacity gains with a reasonable complexity. The space-time codes that have been introduced so far are block codes, leading to the manipulation of possibly large matrices. To reduce complexity, this work introduces convolutive codes, associated with MIMO lters. The proposed approach also constitutes an alternative to OFDM based approaches for frequency fading channels. I. Linear prefiltering approach The assumptions we shall adopt for the proposed approach are: no channel knowledge at TX, perfect channel knowledge at RX, and a matrix channel impulse response spanning L symbol periods. We consider the case of full rate transmission (Ns = Ntx) (Ns;Ntx and Nrx are the number of substreams, transmit and receive antennas). A general ST coding setup is sketched in Fig. 1. The incoming stream of bits gets transformed to Ns symbol substreams through a combination of channel coding, interleaving, symbol mapping and demultiplexing. The result is a vector stream of symbols bk containing Ns symbols per symbol period. The Ns substreams then get coding & mapping channel + demapper & channel decoder T(z) H R(z)